During conventional manufacture of semiconductor wafers, a flat is formed on the original crystal ingot by a grinding process. This flat is for the purpose of establishing crystal direction in the wafer for later device fabrication steps.
One of the steps in wafer manufacture is to round the edge of the wafer by a process known as edge grinding. This step avoids edge chipping at later stages in wafer manufacture. The edge grinding or rounding is usually done by an edge grind or edge contouring machine, which presses a grooved grinding wheel against the end of the wafer as it slowly rotates; the groove in the grinding wheel has the opposite shape of the contour that it is designed to generate. The flat also has to be ground to a beveled profile. The beveled or rounded edge is beneficial because it reduces chipping of the wafer edge during later process steps.
Recently, wafers larger than 150 mm have been produced, and a new standard of locating crystal direction has been adopted, namely a notch. A problem with forming the notch is that the usual edge grinding wheel will not reach the bottom of the notch to bevel it.